Since a single-phase switched reluctance motor (SRM) has a simple electromagnetic structure, a simple driving circuit, and a strong mechanical structure, and can be accelerated or decelerated with a high efficiency, a high torque and a wide operational range. Accordingly, the single-phase switched reluctance motor (SRM) has been widely used in various industrial fields and home electronic appliance fields.
In order to drive the single-phase SRM, a diode rectifier or an AC/DC converter, and an SRM inverter have been used to apply pulse type voltage, which is generated from a voltage source, to the single-phase SRM. The single-phase SRM essentially requires DC voltage. In general, the single-phase SRM has acquired the DC voltage through a circuit including an AC/DC converter and a filter capacitor having a large capacity.
FIG. 1 is a circuit diagram showing the conventional single-phase SRM driving circuit.
Referring to FIG. 1, the conventional single-phase SRM driving circuit includes an inverter circuit having a diode rectifier for rectifying power, which is supplied from a voltage source Vs, into direct current (DC) power and a large-capacity capacitor used to restrict peak torque ripples.
When the single-phase SRM is driven by using the inverter circuit including the conventional large-capacity filter capacitor, the single-phase SRM can restrict peak torque ripples. However, peak AC current flows through the single-phase SRM according to the charge/discharge operation of the large-capacity capacitor, which is connected to the voltage source, so the power factor is remarkably reduced.
Recently, in order to solve the problems, researches and studies have been actively pursued toward a power factor correction (PFC) technique at home and abroad. However, the conventional PFC circuit has complicated control circuits and complicated power circuits. In addition, even though the single-phase SRM is economical or has an improved power factor, torque ripples are seriously caused.